Coiled tubing: the all-rounder of the "universal work machine".
Recently, the China Petroleum and Petrochemical Science and Technology Innovation Conference and New Technology Achievement Exhibition with the theme of "Enhancing Scientific and Technological Innovation Capabilities and Moving Towards High-level Self-reliance and Self-reliance" was held at the China Petroleum Science and Technology Exchange Center in Beijing.
At the invitation of the China Petroleum Society, Qinghai Oilfield's "Integrated Process of Coiled Tube Gas Well Production" participated in the event on behalf of the oilfield, showing the development process of new technologies, new processes and new achievements in Qinghai Oilfield in recent years.
The successful application of the process has improved the efficiency of the new gas well production, reduced the formation pollution, ensured the efficient development of the gas field, provided a boost for the construction of the oilfield coiled pipe assembly demonstration area, and laid the foundation for the promotion and application of the integrated process of coiled tube gas well production in the group and the entire petroleum industry.
In May 2009, when coiled tubing equipment was introduced for the first time in the oilfield, it can be said that a small "wave" was set off. "When I first worked, I thought that if there was a tubing directly to the bottom of the well, without using a tubing to start the operation, it would be great, saving time and effort, and the efficiency was high, but I didn't expect it to be realized!" Zhang Yang, a technician from the coiled tubing operation team of the downhole operation company, was still very excited when he remembered the scene at that time.
Today, after 14 years of leapfrog development, the coiled tubing business in Qinghai Oilfield has continuously expanded the scope of coiled tubing operations, continuously improved its technical capabilities, increased the workload from the initial 15 wells per year to more than 1,000 wells in 2023, and expanded the number of various process types to 32, further broadening the scope of coiled tubing operations.
Coiled tubing equipment
Widely used in oil and gas industry
Drilling, completion, oil production, workover, etc
Multiple areas of technical work
Commonly known as the "all-purpose" work machine
But is it inherently "omnipotent"?
What is its application in oilfield exploration and development?
Today, the editor will take you to find out.
Almighty increase reserves and production
Increasing reserves and production is the foundation and value of oilfield development. After the introduction of coiled tubing operation technology, Qinghai Oilfield combined with the special geographical environment and geological characteristics, through continuous digestion, absorption and innovation, and gradually formed its own characteristic series of technologies, which has paved a characteristic road for the oilfield to achieve increased reserves and production.
The high temperature, high pressure and high salt of the reservoir in Yingxi Oilfield cause the production channel to become smaller or even completely blocked due to salt crystallization in the production process, resulting in the reduction or shutdown of oil wells. According to the characteristics of a single well of high-yield wells in the western part of the country, the technicians have developed the technology of large-diameter salt flushing and plugging removal, and formed a characteristic process of coiled tubing salt flushing and plugging removal in the western part of the country. Since 2020, the oilfield has used large-diameter coiled tubing to flush salt and remove plugging of high-temperature, high-pressure and high-salt oil reservoirs, with more obvious advantages and faster salt dissolution, achieving a maximum depth of 5,400 meters in a single operation and a construction success rate of 100%.
Natural gas is half of the Qinghai oil field. In order to ensure the stable production of the gas field, Qinghai Oilfield has carried out technical research based on the characteristics of gas reservoirs and production problems in each gas field, and formed a series of characteristic technologies such as coiled tubing downward velocity string and nitrogen foam sand washing, which has laid a solid foundation for the stable production and production of the gas field.
With the deepening of the development of Shibei gas field, the water and sand production are intensifying, and the problems of formation pressure decline, serious reservoir blockage, and wellbore complexity are superimposed. In practice, coiled tubing nitrogen foam sand flushing technology effectively solves the problem of easy leakage of liquid in sand flushing in low-pressure gas wells, and has become a demonstration process of nitrogen foam sand flushing in the PetroChina industry. It is reported that in the past three years, more than 1,200 wells have been completed in this process, with an average recovery gas volume of about 5,000 cubic meters per well.
Almighty cost reduction and efficiency increase
Reducing costs and increasing efficiency is a self-revolution for enterprises to improve management efficiency and achieve high-quality development, and it is also an inevitable choice to improve the refined management of enterprises and enhance their development stamina. In recent years, Qinghai Oilfield has continuously promoted the technological innovation of coiled tubing, and currently has 32 coiled tubing processes, which are mainly used to solve various problems in downhole operations in the process of oil and gas exploration and development and assist conventional workover operations to achieve speed and efficiency.
At present, the effect of coiled tubing operation replacing conventional workover operation is gradually emerging, creating a "Qinghai model" of large-scale application of conventional operation. It is reported that the two processes of new well washing and nitrogen foam sand washing have realized "one coiled pipe equipment is equivalent to four workover rigs", and the annual operation volume of a single vehicle is up to 245 wells. Compared with the conventional operation timeliness, the "gas well coiled tubing production and completion integration process" can save 31 hours of operation time and increase the efficiency of a single well by 50%, and the cost of a single well of coiled tubing can be reduced by about 25.2% compared with the rated cost of conventional operation, which greatly improves the efficiency of new gas well production and construction and ensures the efficient development of gas fields.
Almighty safety and environmental protection
In September 2020, China announced at the United Nations General Assembly that it would increase its nationally determined contributions and adopt stronger policies and measures to peak carbon dioxide emissions before 2030 and achieve carbon neutrality before 2060. In recent years, Qinghai Oilfield has been guided by the "dual carbon" goal and deeply rooted the concept of "green oilfield" in all aspects of development.
By realizing pressure operation, coiled tubing operation gives full play to the unique advantages of fast and efficient, clean and environmental protection, and fine stratification. This year, when the "gas well coiled tubing production and completion integration process" was applied for the first time in Shibei Gas Field, the process successfully realized the integrated completion operation of slurry replacement, well penetration, and pressure after perforation, which solved the problems of formation pollution and rapid production decline caused by post-perforation, effectively protected the oil and gas reservoir, made it safer and more environmentally friendly, and truly realized safe workover and green workover.
"At present, there are 32 mature processes of coiled tubing, but we have less promotion and application of some processes in solving actual production problems, and the conventional process is mainly wellbore cleaning accounting for 85.3%, and special processes such as cutting, drilling and grinding, fishing, etc. account for only 14.7%, and the overall process application is still uneven. In the next step, we will actively communicate with the construction unit while doing a good job in the large-scale application of conventional processes, and strive for special process workloads such as cutting, drilling and grinding, and salvage, so as to achieve a balanced development of coiled tubing technology. Zhu Tao of the coiled tubing operation team of the downhole operation company said.
